New concepts for left atrial occlusion devices aim to close off a troublesome pouch in the heart without using sharp wire anchors, but St. Jude Medical’s (NYSE:STJ) Amplatzer Amulet still relies on barbs to keep the device in place, a topic which became a point of concern among panelists during an evening presentation at the Transcatheter Cardiovascular Therapeutics conference.
Representatives for 7 LAA devices touted their technology tonight, most of them in very early stages of clinical study and about half of them veering away from metal tines as a design feature. St. Jude’s recently redesigned Amulet not only retained its metal barbs, the new iteration includes even more barbs than before.
The wire hooks help anchor the device in place in the heart’s left atrial appendage and may help prevent embolization, but the barbs do present a risk of tissue perforation as time goes on, according to Dr. Reda Ibrahim of the Montreal Heart Institute, who presented Amulet data on behalf of St. Jude. Ibrahim defended the barbs as appropriate for the current patient population being considered for LAA implants, but barb-free devices may be the future.
"The ideal device will have no barbs," Dr. Ibrahim told MassDevice.com after the presentation. More studies need to be done to demonstrate that the barbed implants are safe for long-term implantation, but for now the patients receiving the Amulet device are older and sicker. "I think there’s less risk to use a device with barbs in this population," Ibrahim said.
"If we are treating more, in the future, young patients with paroxysmal afib, we need to prove that on the long term we are safe, especially if we are replacing more and more the anticoagulation," he added. "Because in the future the ultimate goal of the device is to replace anticoagulation, even in younger patients."
Some of the up-and-coming device makers presenting their technology tonight have developed novel ways to anchor the implants without needing to claw into the tissue.
"If you can get away with not having to use barbs, that would be incredible. That’s our approach," said Dr. Alexander Javois of Hope Children’s Hospital. Dr. Javois presented data for the PFM Medical, which hopes next year to launch human trials of its pfm LAA Occluder. The pfm device relies on the anatomy of the LAA to anchor the device, wedging the corners of the occluder against naturally occurring ridges in the muscle.
Other devices veering away from metal hooks were the Sideris Patch, which uses a resorbable balloon anchoring method, and Occlutech, which features wire loops rather than barbs.
Dr. Brian Whisenant of Intermountain Medical Center was more defensive of the anchoring hooks, warning that other technologies are touting methods that are largely untested. The WaveCrest implant uses "smaller, less aggressive barbs" similar to Amulet’s approach, according to Dr. Whisenant who co-founded Coherex Medical and presented the company’s barbed WaveCrest LAA occlusion device today.
"I don’t think that there was a sense [during the panel] that barbs are not the way to go. I think there were several devices that said they’re moving away from barbs and so it raises the question," he told MassDevice.com after his talk. "We don’t have any devices without some type of tines or barbs in humans yet with a real track record, so I think it’s too early to say that they’re going away."